When measuring the amount of the target material from the sample of mixture of a large number of chemical substances by either optical or electrochemical method, the result of chemical reaction between the target material and the corresponding material (chemically reacting material) is measured. When one or more other substances causing interference with a procedure for measuring the target material are unfortunately present in a mixture sample, obstruction attributable to such an interfering substance is caused.
Such an obstruction attributable to the interfering substances causes measurement errors to take place with respect to the target material, and thus becomes the principal cause of deteriorating the performance and reliability of products. In order to overcome this deterioration, conventional methods have concentrated their energy on the use of a scheme of previously eliminating interfering substances using chemical processing or a scheme of separately measuring independent values with which remove the effect of interference afterward. These methods are problematic in that the overall measurement process is complicated due to the addition of a chemical processing procedure or a separate measurement procedure, thus requiring high cost, and in that errors that may occur in the separate measurement procedure are accumulated, thus deteriorating accuracy.
That is, most conventional technologies have placed emphasis on the elimination of measurement errors via improvement based on an additional chemical procedure during the measurement process. Such technology is problematic in that qualitative improvement of various types of materials related to the measurement process is required, or a process for eliminating measurement errors is complicated by intending to reduce errors via a multi-step reaction procedure, and in that a process for manufacturing products which follow the above process is complicated, thus increasing the costs of products.
As one conventional technology, Korean Pat. Appln. No. 1989-0014308 (filed on Oct. 5, 1989) discloses “measurement error compensation method and light source control method for a blood glucose meter”.
The conventional technology discloses a measurement error detection routine which emits light to a non-discolored blood sugar test paper required and detects a measurement error using reflected light to measure blood sugar concentration, and a measurement error compensation method for a blood glucose meter which compensates for measurement errors by calculating the value of the light, reflected from the blood sugar test paper discolored according to the blood sugar concentration, and the measurement errors detected by the measurement error detection routine. However, there is a problem because separate measurement errors must be detected in real time using the measurement error detection routine for the purpose of error correction, thus complicating a manufacturing process. Further, the conventional technology does not disclose a method of estimating the feature values of a measurement target material using the temporal change of measured values. Furthermore, the conventional technology is aimed at reducing errors which occur due to the differences between the colors of blood sugar test paper.
As another conventional technology, Korean Pat. Appln. No. 2006-0025890 (filed on Mar. 21, 2006) discloses “test strip for electrochemical biosensors capable of effectively compensating for hematocrit interference.”
The above technology provides a scheme for compensating for existing signal decrement using an electrical signal obtained from the internal material of a red blood cell, which determines hematocrit. In this scheme, a separate electrode is configured, and blood cell interference corrective for reacting with blood cells within a physiological sample and generating charges corresponding to the concentration of the blood cells are included, thus compensating for the existing signal decrement using the electrical signal obtained from the internal material of the red blood cells. However, this technology accompanies complication in a manufacturing and measurement process due to a complicated electrode structure and the provision of separate supplements, and does not disclose the estimation and calculation of the feature values of a measurement target material using the temporal change characteristics of measured values.
As a further conventional technology, U.S. Pat. Nos. 5,708,247 and 5,951,836 (entitled “Disposable Glucose Test Strips, And Methods And Compositions For Making Same) and U.S. Pat. No. 6,241,862 (entitled “Disposable Test Strips With Integrated Reagent/Blood Separation Layer”) disclose a technology for applying a nonconductive material to an electrode system to reduce interference effects on hematocrit, wherein both a method of manufacturing a carbon paste electrode system using screen printing technology and a reagent/blood separation layer fixed onto the surface of the electrode system are described. This conventional technology also includes the structure of the electrode and the application of a separate material, and does not include a technology for estimating and calculating the feature values of a measurement target material based on kinetic change indicating the temporal change of measured values.
Among conventional technologies, as a commercialized product using a thin film-type electrochemical enzymatic electrode, there is YSI 2300 STAT PLUS (Yellow Spring Instrument, Inc.). This technology is characterized in that three types of electrodes, that is, an enzymatic thin film, an external thin film, and an internal thin film, and in that an enzymatic material reacting with an analyte is manufactured as a thin film, and functional macromolecular thin films are manufactured and combined with each other on the inside and outside of the enzymatic thin film, thus effectively preventing red blood cells, protein, etc. from being adsorbed on the surfaces of the electrodes. The thin film-type enzymatic electrode can innovatively eliminate hematocrit interference, but the application of three types of thin films to the electrode system is accompanied by a complicated manufacturing process and high cost, thus increasing blood consumption and lengthening the reaction response time. This conventional technology is also intended to reduce errors using the enzymatic electrode and does not include a technology for estimating and calculating the feature values of a measurement target material based on the kinetic change of the measurement target material.
As conventional technology, Korean Pat. Appln. No. 2006-7003547 (entitled “electrochemical feature analysis method and apparatus” filed on Feb. 21, 2006) discloses a technology for correcting an analyte-dependent signal using analyte-independent signal information so as to more accurately evaluate an analyte, wherein the analyte-dependent signal which is not corrected is corrected based on observed analyte-independent voltage attenuation, and then a corrected analyte-dependent signal is formed. Voltage or current sufficient to cause the oxidation or reduction of an analyte or a medium is produced between two cell electrodes, and a slope in the chemical voltage of the analyte or the medium between the two electrodes is formed by the voltage or current. After the slope has been formed, the analyte-independent signal is obtained from the relaxation of the chemical voltage slope occurring when the applied voltage or current is stopped, and this analyte-independent signal is used to correct analyte-dependent signals obtained during the application of the voltage or current. This conventional technology is intended to perform correction using the signals obtained with the voltage supplied and without the voltage supplied, and does not include a technology for estimating and calculating feature values using kinetic change information obtained with the voltage supplied.
As conventional technology, Korean Pat. Appln. No. 2003-0036804 (entitled “electrochemical biosensor” filed on Jun. 9, 2003) relates to a sensitive layer composite capable of reducing measurement errors corresponding to the amount of hematocrit by decreasing a dependent tendency attributable to the hematocrit difference of blood, and a biosensor including the sensitive layer composite, wherein a technology for reducing errors attributable to an interfering substance using a chemical processing method added to the biosensor is disclosed. However, this does not include a technology for estimating and calculating feature values using kinetic change indicating the temporal change of values measured on a measurement target material.